Defend the Hearth sees competitive metagame play in 1 format(s): Commander
Crab might seem odd here, but we have a lot of ways to get lands into play from our library, so it turns cards like Crop Rotation, Harrow, and Growth Spiral into mill spells
Alternately, if your deck plays discard or countermagic, just wait the extra 1-2 turns to play your important threat with mana up for a same turn TS or Spell Pierce
Samut is a six mana Legendary Creature that costs three generic, one white, one red, and one green
By the way: this is not "legal advice." You can go out and get a lawyer for that, if you ever feel that you need it
Goblins have their Conspicuous Snoops, green tribes have their Allosaurus Shepherd, zombies get to run cards like Zombie Apocalypse, etc